The volume of peer-to-peer traffic between users connected to the same access network has increased over the years. Although end users conducting peer-to-peer traffic are still in the minority, this form of traffic is characterized by large data volumes and consequently represents a disproportionately large share of the total traffic. Internet service providers have to provide more bandwidth to accommodate the traffic and they are also obliged to reduce over-subscription ratios and to increase network capacity. In a flat-rate charging model, these investments bring little or no return, as users pay a fixed fee regardless of the traffic volume generated. During peak hours, contention in best-effort traffic classes could lead to low responsiveness, undesirable delays and packet losses for other services, such as web browsing, leading to low customer satisfaction. Moreover, the ability of the service providers to support subscriber growth rates decreases. More significantly, the inter-exchange fees paid to other carriers for transporting traffic across foreign networks increases.
While peer-to-peer traffic poses a problem to service provider networks, the problem is perhaps more severe within the access networks themselves. Ethernet-based access networks typically use some form of traffic separation to prevent layer 2 connectivity between end users. One such method is forced forwarding, which directs all end-user traffic within the access network to an edge node; direct layer 2 connectivity is hence prevented. One example of forced forwarding is MAC forced forwarding, described in A. Wassen, “Technical overview of public Ethernet”, EAB A-03:002114 Uen, 2003. In this scheme, traffic from all layer 2 access nodes and also from outside the access network is routed or “tunnelled” first to a layer 3 edge node. This node is capable of identifying the source and destination address and the identification of the access nodes and routing the packet to its destination within the access network.
Data collected from broadband access networks indicates that peer-to-peer traffic represents a large proportion of the traffic within an access network. Moreover, with the tendency for building large access networks, the volume of such traffic can only increase, resulting in an inordinately large proportion of the bandwidth between the access and edge nodes being occupied by what is predominantly low priority traffic. There is thus a need to provide a scheme, which, while maintaining traffic separation, ensures that the impact of peer-to-peer traffic on an Ethernet-based access network is reduced.